Process of preserving timber by means of phenolate solutions.



UNITED STATES PATENT FRIEDRICH SEIDENSCHNUR, OF CHARLOTTENBURG, GERMANY.

- FPROCESS 0F PRESERVING TIMBER BY MEANS OF PHENQLATE SOLUTIONS.

No Drawing.

.a full, clear, and exact description of the same.

My invention relatesto processes of preserving timber by tions.

In order to utilize. the preserving property of many phenols, forexample of the naphthols, ill Allie impregnation "of timber, solutionsof the alkali or earth alkali phenolates were' 'introduced into thetimber and the free phenol was precipitated from the solutions by the.action of carbonic acid or of gases containing carbonic acid. Aqueoussolutions ofthe free phenols cannot be employed for impregnating timberon account of the phenols being only slightly soluble in water. Thetimber was impregnated with the phenolate solutions by firstlyevacuating the timber and then introducing the phenolate solution underpressure. Hereupon, carbonic acid or gases containing the same werecaused to act on the timber whose cells were filled with the phenolatesolution. The precipitation of the phenol by the carbonic acid was onlyimperfect. The carbonic acid could act only'on the outer cells of thetimber. The phenol separated in the outside layers rendered diflicultthe further penetration of the carbonic acid. The sodium carbonatesolution formed by the action of the carbonic acid in the outside layersexercised no action on the sodium phenolate solution in the lowerlayers, and did not absorb carbonic acid at all or only in' very smallquantities. For this reason the carbonic acid did not pass through theliquid into the lower layers. The inner cells of the timber thuscontained undecomposed phenolate solution. posed process'consisting infirstly filling the pores of the Wood with carbonic acid and thenintroducing phenolate solution into the timber had the defect that thequantity of phenol actually put into the wood was much too small forenabling the antiseptic action of phenol to be effective in all thecells of the Specification of Letters Patent.

' timber, as described above.

means of phenolate solu- Another pro-.

latented AW. 6, 1912.

Applicatio iiifiled May 8, 1912. Serial No. 695,877.

timber, including the inner cells. The phenol was separated in the outerpores of the The penetration of the carbonic acid into the lower layersof the timber was prevented for the same reasons as in the known processdescribed above. The solution of sodium carbonate formed in the verynarrow capillary tubes constituting the cells of the timber rendersdifficult or prevents the deep, penetration of carbonic acid.Antiseptically acting phenol is therefore lacking in the inner cells.

A primary object of my invention is to provide a process of preservingtimber by means of phenolate solutions to which these defects are notattached.

To this end, my improved process conquantity of phenolate insufficientfor filling the pores and then distributing the phenolate solution inthe pores sothat substantially only the walls of the pores areimpregnated with the phenolate solution, while the chambers in the poresremain free from liquid. The gas contained in the pores is thenevacuated, whereupon carbonic acid or gases containing carbonic acid isor are introduced into the pores. For example, the timber may first befilled under pressure with a gas free from carbonic acid,

e. 9. air liberated from carbonic acid, whereupon phenolate solution isintroduced while increasing the pressure in the impregnation tank. Thegas which is present is allowed to escape out o'tf the impregnation tankor cylinder according as the phenolate solution flows in when fillingthe cylinder. After the phenolate solution has acted sufficiently, thepressure is done away with and the gas evacuated in order to remove thephenolate solution'from the interior of the cells of the timber. Ifdesired, I may first introduce a large quantity of sodium phenolatesolution into the timber without subjecting the same previously toevacuation, then run ofi' the impregnation liquid out of theimpregnation tank and, by evacuating once or more times, remove theexcess, of sodium phenolate solution outof the timber and simultaneouslydistribute the residue through the entire mass of the timber.

Further, if desired, a small quantity of indifferent gas free fromcarbonic acid or by steam. After the phenolate solution hasbeen'distributed in the interior of the timber Carbonic acid or gasescontaining car-' bonic acid is or are inserted into the timber.

After the removal of the gas in the poresacid in thepresent case, hashowever not heretofore been employed for this purpose. Nor has it beenproposed to precipitate phenols on the walls of the cells and to produceconsiderable antiseptic action with small quantities of phenols owingto. the

difliculty of dissolving the precipitated phenols.

My improved process may be carried into practice as follows :The timberto be impregnated is put into animpregnation tank of known kind. Thetimber is first .subjected in the, tank to an air pressure of 1?;atmospheres forabout half an hour. It is then impregnated with a sodiumphenolate solution of about 4% at a temperature of C. A liquid pressureof 8 atmospheres is now produced and maintained for one -The evacuatedtimber is then treated for half an hour with carbonic acid at a pressureof 4 atmos. l, 4 I claim: I lrA process of preserving timber by means ofphenolate solutions which con-Y. sists in impregnating the timber with aquantity of a phenolate' solution insufficient 4 for completely fillingthe cells of the timber, in uniformly distributing the phenolatesolution in the timber and in subsequently introducing carbonic acid gasinto the pores of the timber. 5

2. A process of preserving timber by means of phenolate solutions whichconsists in impregnating the timber with a quantity of a phenolatesolution insufiicient for com- 4 pletely filling the cells of thetimber,' in 5 uniformly distributing the phenolate solution in thetimber and in subsequently introducing a mixture of gases containingcarbonic acid gas into the pores of the timber.

In testimony whereoLI have signed my name to this specification in thepresence HENRY HAsPER WVOLDEHAR HAUPT.

